Engine starter



Jan. 14, 1936. c. cuNNnJs 2,027,860

" ENGINE STARTER Filed Feb. 27, 1931 2 Sheets-Sheet l In venior CALu/N Ca/v/v/z/ot A llomey Patented Jan. 14, 1936 PATENT OFFICE ENGINE STARTER Calvin Cunnius, New Brunswick, N. J assignor to Eclipse Machine Company, Elmira Heights, N. Y., a corporation of New York Application February 27, 1931, Serial No. 518,867

3 Claims.

This invention relates to improvements in engine starters.

The primary object the invention resides in an engine starter construction which eliminates the use of coacting threads between the driven starting pinion and its driving connection, which is the type of starter now in general use. By such elimination, I am able to materially reduce the number of working parts and the cost of manufacture.

Another object of the invention is to provide an engine starter in which the end thrust usually caused by the driven pinion moving intoengagement with the gear teeth on the engine fly wheel is eliminated, and the damaging result caused by such thrust is thus avoided.

A further object is the provision of an engine starter in which two helical springs with their convolutions threaded one within the other, coact to provide a driving medium between the starting engine drive shaft and the driven starting pinion, and which further produces the necessary force to return the starting pinion to its normal inoperative position.

A further feature is to produce an engine starter which is substantially noiseless, and strong and durable in operation.

With these and other objects in view, the invention resides in the certain novel construction, combination and arrangement of parts, the essential features of which are hereinafter fully described, are particularly pointed out in the appended claims, and are illustrated in the accompanying drawings, in which:

Figure 1 is a side olevational view partly in section of my improved starting device with the parts in retracted or normal position.

Figure 2 is a similar view but showing the parts in operative or extended position.

Figure 3 is a vertical transverse sectional view on the line 3-3 of Figure 1.

Figure 4 is a vertical transverse sectional view on the line l l of Figure 1.

Figure 5 is a fragmentary elevational view showing the manner in which the inner ends of the two spring elements coact.

Figure 6 is a vertical longitudinal sectional view of a slightly modified form of my invention.

Figure '7 is a vertical transverse sectional view on the line 1-1 of Figure 6.

Referring to the drawings by reference characters, and especially to Figures 1 to 5 inclusive, the numeral ID designates the drive shaft or armature shaft of the starting motor of an internal combustion engine and II the fiy wheel thereof provided with an annular gear l2. Keyed to the drive shaft H] as at I3 is an annular collar M, while also fixed to the shaft adjacent the free end of the same is a stop collar or nut l5. Slidable upon the shaft I0 is a driven or starting pinion gear l6 which comprises a toothed body I! provided with a reduced threaded portion Hi to which an eccentric nut or weighted member I9 is threadedly connected. Interposed between the nut l9 and a shoulder formed in the body portion IT by the reduced portion I3, is a stop collar or flange 20. Thus it will be seen that the body portion ll, nut l9 and stop collar 20 are rigidly connected together and are adapted to move as a single unit.

Surrounding the drive shaft 10 and connected to the collar It and driven pinion H are coacting helical springs 2! and 22 respectively. The inner end of the spring 2| is provided with an angularly extending finger 23 which is fixedly received in an opening provided in the inner face of is collar Id, while the inner end of the spring 22 is likewise provided with an angularly bent finger 24 for reception in a recess provided in the body of the pinion I! and which is fixedly received in said recess. The outer end of the helical spring 2! terminates in an outwardly bent finger 25, while the outer end of the helical spring 22 terminates in an outwardly bent finger 26 as best seen in Figure 5 of the drawings. The

convolutions of one of the springs are threaded with the convolutions of the other spring whereby a threading action will be produced upon rotation of the drive shaft ID. The terminal ends 25 and 26 of the spring are disposed in the path of movement of each other in order to abut or engage when the spring member 22 is threaded outward to the limit of its threading movement with respect to the helical spring 2i as shown in Figure 2 of the drawings.

In practice, assume that the parts are in inoperative position as shown in Figure l of the drawings, whereupon the two springs are threaded to the limits of their inward threading movement, at which time the convolutions of the respective springs are in close proximity to each other. The pinion I6 is in spaced relation with respect to the gear teeth [2 of the. fly wheel II, but upon rotation of the shaft 10, the spring 22 is threaded outward by the turning of the spring 2| and after reaching the limit of its outward threading movement, the finger 26 on the spring 22 abuts the finger 25 of the spring 2| and further rotation of the shaft causes a tension to be placed upon the respective spring members.

When such tension is placed upon the springs, the teeth of the pinion [6 are in meshing engagement with the teeth l2 of the fly wheel H, whereupon power is transmitted from the drive shaft ID to the fly wheel in order to impart rotation to the fly wheel for the starting of the internal combustion engine. It will therefore be seen that a resilient driving connection is provided between the drive shaft l0 and the fly wheel of the engine, and the pinion is returned to its normal position by reason of the tension placed upon the spring members when the same have been expanded to cause the pinion I6 to fully mesh with the teeth l2 of the fly wheel.

In order to prevent accidental movement of the spring members 2| and 22 when the parts are in normal or inoperative position, I provide detents or recesses 21 in the outermost convolutions of the spring members which receive the rounded heads of pins 28. The pins 28 are slidably mounted in the collar l4 and eccentric nut l9, and which headed portions open through the inner faces of these parts. The pins 28 are moved outward by springs 29, the tension of which is only sufficient to ternporarily hold the two springs against accidental movement. It will of course be understood that when the drive shaft l0 rotates, the pins will release the outer free ends of the two spring members.

In Figures 6 and 7 of the drawings, I have illustrated a slightly modified form of my invention wherein a tubular shaft or sleeve 30 is keyed to a drive shaft 3| as at 32. An annular collar 33 is threaded or otherwise secured to the inner end of the tubular shaft 30 while a stop nut or collar 34 is threaded to the opposite end. The driven starting pinion 35 is slidably mounted upon the tubular shaft 30 and is of the same construction as that hereinbefore described. The starting pinion 35 is operatively connected to the collar 33 in the same manner as that shown in the preferred form, that is by reason of a resilient connection 36 composed of two helical springs with their convolutions interthreaded and with their inner ends fixedly secured to the collar 33 and pinion 35 and being provided with coacting fingers on their inner ends for the same purpose as hereinbefore mentioned.

The construction shown in the modified form permits of the assembling of the parts upon the tubular shaft 36 prior to the insertion of the same upon the drive shaft 3| in order to provide a unit for attachment to: a drive shaft as it is only necessary to slide the tubular shaft 30 over the drive shaft 3| and key the same together when installing the starting device upon the armature shaft of the starting motor.

Although I have shown and described the coacting helical springs as being round in cross section for reducing friction between the convolutions to a minimum, it will be understood that the convolutions may be of other configuration in cross section if desired, without in any way departing from the spirit of the invention.

From the foregoing description, I have provided a starting device which dispenses with the general construction of threadedly connecting the driven pinion with the drive shaft and which threading is a very costly procedure. Furthermore, I have so constructed the device soas to reduce the number of parts to a minimum without sacrificing strength and durability. In the event that any of the parts should become damaged, the same may easily be removed and a new part substituted therefor.

While I have shown and described what I deem to be the most desirable embodiment of my invention, I wish it to be understood that various changes in construction may be resorted to if desired, without departing in any way from. the spirit of the invention and I therefore do not limit myself to anything less than the whole of the invention which is limited only by the appended claims.

Having thus described the invention, what I claim as new and desire to secure by Letters Patent is:-

1. In combination with a rotatable shaft, a driving member fixed to said shaft, a driven member slidable on said shaft, 2. pair of helical springs with the convolutions of one threadedly connected with the convolutions of the other, the outer ends of the springs being respectively connected to said driving member and said driven member, coacting stop elements provided on the inner ends of said springs and disposed in the path of movement of each other for forming a resilient driving connection between said driving member and said driven member, and coacting catch elements between the innermost convolutions of said springs and said driving member and driven member respectively for temporarily holding said springs against movement when the same are in fully retracted position.

2. In a starter drive a hollow sleeve, a driving member fixed to the sleeve, a driven member slidable on said sleeve into and out of engagement with a member of an engine to be started, a pair of helical springs with the convolutions of one threadedly connected with the convolutions of the other, the outer ends of the springs being respectively connected to said driving member and said driven member, means on said sleeve for limiting the separation of the driving and driven members, and a yielding detent for resisting movement of the driving member out of its idle position.

3. In combination with a rotatable shaft a driving member fixed to said shaft, a driven member slidable on said shaft, a pair of helical springs with the convolutions of one threadedly connected with the convolutions of the other, the outer ends of the springs being respectively connected to said driving member and said driven member, and retaining means cooperating between the innermost convolutions of said springs and said driving member and driven member respectively for temporarily holding said springs against movement when the same are in fully retracted position.

' CALVIN CUN'NIUS. 

